Sound bulb



FIG. 1 is a side elevational view of a sound bulb showing my new design, with the opposite sides being a mirror image;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1; and,

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1. 

CLAIM The ornamental design for a sound bulb, as shown and described. 